Abstract: A free fibre or loose fibre structure for padding comprising a shell containing a plurality of free or loose fibres, said structure being characterised in that said free or loose fibres have a cut that reproduces the length, and in part the fineness, of genuine goose down.

Abstract: The invention is in the field of devices for producing particles, in particular large agglomerate particles.

Abstract: The invention is in the technical field of particles; more particularly, the invention relates to large agglomerate particles obtainable by spray-drying agglomeration.

Abstract: A vacuum system is configured to segregate debris on a conveyor belt. The vacuum system includes a manifold further comprising a manifold body joined to a first end wing and a second end wing. The manifold body further includes a tube slot opening joined to a tube slot. A vacuum tube adapter is joined to the tube slot. A vacuum tube adapter flared portion is arranged on the vacuum tube adapter. The vacuum tube adapter flared portion is adapted to receive a flexible vacuum intake hose. A first end flap further includes a first end flap central opening, and joined the first end wing. A second end flap further includes a second end flap central opening, and joined the second end wing.

Abstract: A fluidized powder heat treatment classification assembly includes a gas source. A fluidized bed is connected to the gas source via a metered connection. The fluidized bed includes a first output connected to a powder classifier via at least a first valve. The powder classifier includes a catch container operable to decelerate a gas flow from the output and operable to catch particles entrained in the gas flow.

Abstract: A separator may include a housing with a separation space in which a ventilation base is disposed and in which separation stock is perfusable by separation gas so as to separate fine stock from coarse stock. A separation-gas inlet and a separation-stock inlet may open into the separation space, and a fine-stock outlet and a coarse-stock outlet may lead out of the separation space. A bypass duct may be integrated in the housing for bypassing the separation space. The bypass duct may lead out of the separation-gas inlet and open out downstream of the separation space.

Abstract: A cleaning arrangement for a sugarcane harvester with a cleaning chamber includes a deflector body with at least one deflection surface at least partly facing a feed stream of cane billets and other material from a feed train of a sugarcane harvester. The deflector body may be fixed to the sugarcane harvester such that the at least one deflection surface extends at least partly within the cleaning chamber. As the feed train moves the feed stream to the cleaning chamber, the at least one deflection surface may deflect at least a portion of the feed stream within the cleaning chamber.

Abstract: A method of processing bagged refuse includes pneumatically conveying filled refuse bags along a conduit using an airflow and opening the bags during the pneumatic conveyance. An apparatus for carrying out the method includes a conduit configured to pass an airflow to pneumatically convey bagged refuse along the conduit and a bag opening structure arranged to open the refuse bags during pneumatic conveyance along the conduit. The open bagged refuse is sorted into fractions using the airflow by passing the refuse across an opening through which the airflow continues. A wall is arranged in the path of travel of the pneumatically conveyed refuse to disaggregate the refuse by impacting the refuse against the wall. The wall is arranged vertically and at least partially defines an opening through which the air stream continues such that a fraction of the refuse falling across the opening is conveyed through the opening.

Abstract: The present invention harvests and utilizes fluidized bed drying technology and waste heat streams augmented by other available heat sources to dry feedstock or fuel. This method is useful in many industries, including coal-fired power plants. Coal is dried using the present invention before it goes to coal pulverizers and on to the furnace/boiler arrangement to improve boiler efficiency and reduce emissions. This is all completed in a low-temperature, open-air system. Also included is an apparatus for segregating particulate by density and/or size including a fluidizing bed having a particulate receiving inlet for receiving particulate to be fluidized. This is useful for segregating contaminants like sulfur and mercury from the product stream.

Abstract: A separator for separating trash into its constituents. An inlet conduit accelerates the trash mixture into an expansion chamber allowing the lighter weight materials to move apart from heavier materials. An air fan applies air pressure to the lighter weight materials drawing off the lighter weight materials while the heavier materials fall towards a collecting conveyor by the force of gravity.

Abstract: Disclosed is a separation apparatus comprising a conveyor; and a material separator positioned above a conveyor, the conveyor being arranged to convey a mixture of materials to the material separator; the material separator comprising a suction duct comprising a sidewall which defines a passageway linking an inlet positioned adjacent the conveyor to an outlet positioned away from the conveyor; and an airflow generator arranged to blow air through a slit in the sidewall into the passageway at a position between the inlet and the outlet; wherein, in use, the airflow generator blows air through the slit in a direction which is towards the outlet for creating a pressure difference between the inlet and the outlet thereby generating an airflow which causes relatively low density materials to be lifted from the conveyor and sucked into the passageway.

Abstract: Apparatus and method for separating lightweight waste from product with cyclic pulses of air. An air separator includes a blower duct directing air upward through product conveyed on a foraminous conveyor. A pair of counter-rotating vanes in the blower duct cyclically open and close to establish a pulsating air flow in the center of the duct across the width of the conveyor. The pulsating air flow lifts lightweight waste from the product and blows it through a vertical duct above the conveyor to waste separation chambers for separation and disposal.

Abstract: A cart is towed behind a combine harvester for collecting corn cobs and includes a conveyer belt feeding into a system for separating cobs from residue to be discharged and a tank for receiving and transporting the cobs. An unload auger is provided from the tank to one side of the cart while the cart moves forward. Power for driving the cart is obtained from a chopper drive of the combine harvester. The separating arrangement includes a series of sequential blower fans for blowing air through the discharged material as it is discharged from a conveyor and into a spreading guide disperses the residue. The cobs are conveyed using a series of augers where the auger to flight distance is at least 2 inches and particularly a pair of augers feed the cobs through a front wall of the tank so as to push cobs upwardly into the tank.

Abstract: A process for the production of a range of improved biomass material products suitable for use as a fuel and which have been derived from municipal solid waste (MSW). The process comprises the steps of delivering a stream of mixed, MSW derived biomass material into a separator which operates under negative pressure enabling the biomass material to fall down the separator while inducing a sole air stream through the falling material to create a vortex of spinning material within the turbo chamber to separate out by centrifugal action selected denser components of the biomass material enabling such to continue falling to an outlet for collection while redirecting by entrainment in the air stream the remaining biomass material to a second outlet for subsequent processing or for collection.

Abstract: Disclosed is a waste separation apparatus comprising a vortex initiator (10) and a vortex generator (20). The vortex generator (20) is arranged to direct the airflow from the vortex initiator (10) towards the waste to be separated. The airflow is used to separate less dense waste from more dense waste.

Abstract: A system and method sorts bulk material containing lightweight components and heavier components, by separating the lightweight components from the heavier components. The method includes the steps of a) conveying the bulk material to be sorted, and releasing it through a corresponding outlet along a given trajectory; and b) generating an airflow and projecting said airflow adjacent to the outlet so that the airflow intersects the given trajectory of the bulk material, and draws along with it the lightweight material via a Venturi effect, thereby separating the lightweight components from the heavier components. This enables namely to easily, quickly and inexpensively sort out fairly lightweight materials, from heavier materials, at a substantial high throughput.

Abstract: A separation system includes an air separator that in one embodiment primarily receives Municipal Solid Waste (MSW) containing relatively light MSW recyclable materials such as paper, cardboard, plastic containers, and/or metal containers. The air separator blows the relatively light MSW recyclable materials up though a chamber and onto a first conveyer while the other relatively heavy MSW material drops down a chute onto a second conveyer. A separation screen receives the relatively light MSW recyclable materials from the air separator and separates the relatively flat paper and cardboard from the plastic and metal containers.

Abstract: Disclosed is a separation apparatus comprising a conveyor; and a material separator positioned above a conveyor, the conveyor being arranged to convey a mixture of materials to the material separator; the material separator comprising a suction duct comprising a sidewall which defines a passageway linking an inlet positioned adjacent the conveyor to an outlet positioned away from the conveyor; and an airflow generator arranged to blow air through a slit in the sidewall into the passageway at a position between the inlet and the outlet; wherein, in use, the airflow generator blows air through the slit in a direction which is towards the outlet for creating a pressure difference between the inlet and the outlet thereby generating an airflow which causes relatively low density materials to be lifted from the conveyor and sucked into the passageway.

Abstract: A deflector device for improving particle distribution within a coal piping system includes a base defining an outer circumference. The base is configured to be mounted inside a pipe such that the base extends partially around the inner circumference of the pipe with the circumferences of the pipe and base being substantially aligned concentrically. A deflector extends radially inward from the base. The deflector is configured to direct a concentrated flow of coal particles toward the center of the pipe.

Abstract: The washing of items of linen is preceded by a plurality of treatments. The items of linen have to be singled out and sorted. In addition, processes for transferring the items of linen are required. In the past, items of linen have been singled out, sorted and transferred in an only partly automated manner. Manual activities are therefore still required. The invention provides for the items of linen to be singled out automatically, the singled-out items of linen to be transferred automatically from a conveyor to a transportation device, various sorting criteria to be determined automatically, in particular the color and the structure of the items of linen, and finally the items of linen to be sorted automatically in accordance with the detected sorting criteria in that they are blown downward at the intended point of a distributor conveyor. The measures according to the invention render manual activities superfluous.

Abstract: A separation system includes an air separator that in one embodiment primarily receives Municipal Solid Waste (MSW) containing relatively light MSW recyclable materials such as paper, cardboard, plastic containers, and/or metal containers. The air separator blows the relatively light MSW recyclable materials up though a chamber and onto a first conveyer while the other relatively heavy MSW material drops down a chute onto a second conveyer. A separation screen receives the relatively light MSW recyclable materials from the air separator and separates the relatively flat paper and cardboard from the plastic and metal containers.

Abstract: An apparatus for segregating particulate by density and/or size including a fluidizing bed having a particulate receiving inlet for receiving particulate to be fluidized. The fluidized bed also includes an opening for receiving a first fluidizing stream, an exit for fluidized particulate and at least one exit for non-fluidized particulate. A conveyor is operatively disposed in the fluidized bed for conveying the non-fluidized particulate to the non-fluidized particulate exit. A collector box is in operative communication with the fluidized bed to receive the non-fluidized particulate. There is a means for directing a second fluidizing stream through the non-fluidized particulate as while it is in the collector box to separate fluidizable particulate therefrom.

Abstract: Disclosed is a waste separation apparatus comprising a vortex initiator (10) and a vortex generator (20). The vortex generator (20) is arranged to direct the airflow from the vortex initiator (10) towards the waste to be separated. The airflow is used to separate less dense waste from more dense waste.

Abstract: An apparatus for separating a mixed particulate material into particles of at least two different specific gravities or ranges of specific gravity, wherein the apparatus comprises an air compressor for providing compressed air into the discharge tube, which, through the venturi effect, creates a vacuum in a connecting hose. The connecting hose is connected to the top of a separation chamber wherein the mixed particulate material, which is vacuumed in by a vacuum hose, is separated and the particles fall into a hopper, while the lighter material is discharged from the discharge tube by virtue of the vacuum created by the flow of compressed air. A conveyor can be used to collect either or both of the lower and higher specific gravity materials, and bring them to other locations. A number of different sensors can be added to the automatic unloader valve to determine when a pre-determined amount of material has been collected.

Abstract: An air classifier to separate solids by air classification while eliminating emissions. The air classifier includes an in-feed delivery mechanism, such as a continuous conveyer belt in order to deliver solids to an input chamber. A hanging curtain is movable in response to solids entering the input chamber. A balanced gate moves in response to solids exiting from the input chamber. An air fan delivers forced air to an air classifier chamber which is in communication with the input chamber. A heavy fraction discharge is in communication with the air classifier chamber to receive a portion of the solids heavier than the force of air delivered to the air classifier chamber. A light fraction discharge in communication with the air classifier chamber removes light solids. A return air duct in communication with the light fraction discharge returns air from the light fraction discharge to the fan. A bleed-off duct delivers a portion of forced air from the fan back into the input chamber.

Abstract: A process, a means of transferring mineable material from any number of sources to a number of devices capable of separating out values from that mineable material. See (FIG. 1) the mineable material enters the hose (1), the hose (1) being under vacuum, and is transferred in a flow of air to the upper portion of a hopper (2). The hopper (2) is also under vacuum. The flow of air leaves the upper portion of the hopper (2) through hose (4), which is connected, to a vacuum blower (5). The mineable material, being heavier than air is deposited in the hopper (2). The mineable material is removed from the bottom of the hopper (2) by means of a variable speed drive screw conveyor (3) and is transferred to a separation device (8). The level of heavy mineable material (6) contained in the hopper (2), along with the mineable material contained in the screw conveyor (3) causes a seal against the force of vacuum and allows the mineable material to enter and be removed from hopper (2) simultaneously if desired.

Abstract: A granular semiconductor material transport system capable of continuous, non-contaminating transfer of granular semiconductor material from a large source vessel to a smaller and more manageable target vessel. Movement of the granular material is induced by flowing transfer fluid. The system includes a source vessel, a feed tube, a process vessel, a target vessel and a vacuum source, or mover. The source vessel contains a bulk supply of granular material to be transported. A feed tube received within the source vessel transfers the granular material entrained in a transfer fluid from the source vessel to the process vessel. The process vessel separates the granular material from any dust particles and deposits the granular material in the more manageable target vessel. The vacuum source sealably connects to the process vessel to evacuate the process vessel to set the granular polysilicon in motion within the system.

Abstract: A parts separator is provided for separating undesired heavy material from wet chips. The parts separator is adapted to be attached to a centrifugal separator, and includes a first chute member having a top portion and a bottom portion and including spaced open first and second chute ends. The first end is adapted to receive wet chips to be centrifuged and the second end is adapted to be connected to a centrifugal parts separator. The parts separator also includes a heavy material drop out opening disposed in the first chute member bottom portion. The first chute member top has at least one opening disposed therein. The parts separator also includes a second chute member having spaced open first and second ends. The first end of the second chute member is adapted to receive wet chips to be separated and the second chute member end is attached to the first chute member at the location of the opening in the first chute top portion.

Abstract: A printing press having an actuator, includes a chamber partly surrounding the actuator and having a pressure prevailing therein that is greater than the pressure in the outer surroundings of the chamber.

Abstract: In order to separate two classifiable materials, a material classifying apparatus includes a vibratory conveyor for conveying a fluidizable material from a material to be separated therefrom from an inlet end through a material separation section to an outlet end located downstream of the material separation section. A plenum chamber directs air upwardly through the fluidizable material and the material to be separated therefrom in the material separation section of the vibratory conveyor to cause fluidization of the fluidizable material and separation of the material to be separated therefrom by forming the material separation section to include a fluidizing deck for supporting the two classifiable materials while accommodating passage of air upwardly from the plenum chamber therethrough.

Abstract: An installation for decontaminating a radioactively contaminated surface with a dry mechanical abrasive includes an extractor for suction extraction of an extraction gas together with an abrasive/dust mixture produced during blasting. A separator separates the abrasive/dust mixture aspirated by the extractor into a dust fraction and a re-usable abrasive fraction. A storage bin is connected between the extractor and the separator. The storage bin includes a filter device having a filter for filtering the extraction gas flowing through the storage bin to the extractor, and a blowoff line to be connected to the filter device for blowing off the filter.

Abstract: In a processing line for processing a leafy vegetable, particularly lettuce, the leafy vegetable is cut into preselected sized pieces which includes high density cores, hearts, ribs, and veins, and low density desirable cut leaf. A gravity/air separation device is provided to separate the high density undesirable parts of the leafy vegetable from the low density desirable leafy vegetable material.

Abstract: A chamber has an aperture which opens downwardly to the atmosphere and an upwardly opening air return passage. A nozzle-forming duct is inclined upwardly at approximately sixty degrees to the horizontal, and a fan mounted therein directs moving air into the chamber. An upwardly inclined ramp is positioned within the duct, and communicates between the chamber and a downwardly opening hole in the floor of the duct. A metered supply of wood chips is fed down a sixty degree incline onto the ramp through the air stream which is moving through the duct. Lightweight chips become entrained in the air and are separated from the rocks, tramp metal and knots which slide down the inclined surface and exit through a hole in the duct. The entrained wood chips, together with the air from the fan, are directed into a curved baffle spaced within the chamber. By forcing the air and chips to move in a curved path, the curved baffle uses centrifugal force to separate the chips from the air stream.

Abstract: A method for preventing corrosion of a reinforced concrete structure having a reinforcing steel embedded therein, which comprises coating an aggregate-containing primer on the surface of the reinforced concrete structure, to form a primer layer having a rough surface, metal-spraying a metal having an ionization tendency larger than iron on the primer layer to form a metal spray coating layer, and connecting the metal spray coating layer and the reinforcing steel by an electrically conductive material.

Abstract: Granule production is based on particle growth in a fluidized bed (4), in which the liquid starting product is sprayed into the fluidized bed and the finished granular particle is discharged from the fluidized bed (4) with classification. The classification is carried out with the aid of a classifying air flow which is divided into individual single flows (6) to each of which is assigned a zigzag classifier module (7, 17) and a spray nozzle (5) or a group of spray nozzles. The course of the classifying process is such that the granular particles which are too small and have not yet reached the desired diameter are thrown back into the fluidized bed (4) by a return shaft (9, 18) seated on each of the zigzag classifier modules (7, 17) in parallel or radial zones without cross-mixing, in which the relatively small particles impinge at a relatively large distance from the return shaft (9, 18) and the large particles, which have already grown close to the discharge size, impinge at a relatively small distance.

Abstract: A conveying and separation assembly for the impact material of a ballistic projectile arrester for indoor firing grounds, of the type that comprises a heap of granulated material as the impact material, and a pneumatic conveyor for sending the granulated material once it has been separated from the exploded projectiles up to the top of said heap. The assembly comprises a variable-diameter worm screw or helical screw, that rotates about a horizontal axis and is arranged within a half cylinder which is open at its upper portion, the worm screw lying in a direction substantially parallel to that from which the projectiles come; a motor for the worm screw; and gravity separation of the exploded projectiles from the granulated material; the half cylinder being connected, at its rear terminal part, with the worm screw or pneumatic conveyor which are employed for sending the material to the top of the heap.

Abstract: A method and apparatus for sorting articles with small density differences utilizing a flotation stream. A separator is provided in which a flotation stream continuously flows through a trough and is used to effect the separation of a mixture of articles having small density differences into several groups. Each density group of the mixture of articles to be separated is introduced at the head of the flotation stream at a selected depth. In one embodiment, the flotation stream may be comprised of a fluidized bed which is created by forcing a gas upwardly through a fluidization medium such as sand. In another embodiment of the invention, the flotation stream may be formed from a liquid.

Abstract: A rotary drum solid waste air classifier includes an inclined drum in which is mounted a non-rotatable separation enhancing tube which extends longitudinally completely through the drum. A waste conveyor is longitudinally mounted within the tube. The feed end of the waste conveyor is located outwardly of the lower end of the tube for receiving solid waste and conveying it through the rotating drum. The tube has a delivery cut-out at and below the discharge end of the waste conveyor so that the waste may fall from the discharge end of the waste conveyor and the discharge from the lower end of the drum while the light fraction flows up the drum and into a plenum downstream from the drum.

Abstract: A fluidized, dry bed, ore concentrator in which a uniform air stream is utilized to fluidize ore particles within a region defined in part by two, moving, riffled surfaces. The particles are statically charged to enhance separation of particles within the fluidized mass. The less massive of the like-charged, fluidized particles are drawn off by a first riffled surface and denoted "tailings". The more massive, and valuable, of the particles are drawn off by the second of the two riffled surfaces and denoted as "fines".

Abstract: An apparatus for the separation of a mixture of particulate material having particles of substantially the same particle size. The apparatus comprising a wind tunnel (10) having an entry and an exit. The exit is associated with a fan (14) for creating an air flow through the wind tunnel (10) from the entry to the exit. An inlet (18) is provided at the top side of the wind tunnel for introducing the particulate material into the wind tunnel whereby it can fall freely under the influence of gravity transverse to the air flow. A plurality of collectors (20) are spaced axially along the bottom of the wind tunnel, each collector extending transversely across the wind tunnel.

Abstract: A resilient liner is provided on the particle supporting surface(s) of a vibratory conveyor system. The liner accounts for a live surface that counters the tendency of the particles, particularly those that are moist and sticky, from adhering to each other and the conveying surface. The liner is particularly effective in systems such as separating systems wherein the particles at various stages fall to other levels.

Abstract: Product, such as grain, is cleansed of particulate, such as dust, as it is being conveyed in the normal receiving, storage, and shipping processes. The particulate is sucked from the product by large volumes of low velocity air. The particulate is sucked from the product at a time that the product is near a port in the side of a discharge transition of the conveyor. It is sucked at the discharge transition because at that point, the grain is in motion and agitated, as well as being near the walls of the conveyor. Furthermore, the conveying of product will create a wind or movement of air which airs the sucking of the particlate from the product. The fan causing the suction is placed as near as possible to the conveyor so that the air and particulate, once removed, is moved through the particulate pipes under pressure rather than under suction. Also, all of the particulate pipes carrying the particulate and air are at an angle greater than 55.degree.

Abstract: Waste material classifying apparatus for applying forced air streams to the waste material discharged off the end of a rotary disc screen conveyor, directing the forced air streams into an enclosure at the discharge end of the conveyor, and forming separate passages in the enclosure so that the waste material fractions are classified by the response of the fractions to the forced air or lack of response to forced air streams, whereby the forced air streams tumble and flip the waste material for augmenting the separation of the fractions.

Abstract: A device for simultaneously separating cohesively bonded particles, by the action of a turbulent air stream, and classifying them according to their size, the device has a horizontal hood connected to the upstream and downstream air ducts. Equipped with an air fan, the upstream air duct has a converging section to accelerate a stream of air. Feed hoppers distribute the particles into the upstream end of the hood where they are separated and classified. Collecting devices are below the hood to receive the classified particles. A recirculating air duct is disclosed including a built-in filter device. A method is also disclosed for simultaneously separating cohesively bonded particles and classifying them according to their size.

Abstract: A ballistic projectile arrester having a regeneration and/or recovery system for the impact material, and which is particularly suitable for the recovery of projectiles fired by small arms or the like in indoor firing ranges or shooting galleries is disclosed. The projectiles are fired into a quantity of granular material which is preferably fireproof and capable of dissipating the kinetic energy of projectiles in a safe way. The granular material is supported so as to provide a sloping surface having a maximum thickness at the point of penetration of the projectiles into the granular materials. The mixture of materials and projectiles is kept circulating in such a manner that the projectiles absorbed by the granular materials can be removed and the granular materials can be continuously recycled back into the separator to replenish the materials which have been removed from the impact area.

Abstract: A rotary feeder for simultaneous screening and discharging of material from the bottom part of a fluidized bed reactor. The rotary feeder is provided with a rotor having blades, between which pockets are formed. In the rotary feeder there is disposed an air inlet and an air outlet for accomplishing a flow of air through the pocket after it has moved over the inlet of the supply material.

Abstract: Apparatus and system for carrying out the air separation of waste wherein the waste is transported by conveyor to the input location of the housing of the apparatus, whereupon it is dropped. A fan having a selectively directed dual airstream is positioned to provide airstream interception of the material stream falling to a confrontation region. Baffling is provided to substantially eliminate turbulence as may be caused by the fan. Separation is developed at three outlets beneath a plenum of the apparatus and a deflector is positioned between that outet receiving organic and that outlet receiving plastic categorized materials. To improve separation, deflectors are mounted vertically on the housing walls to increase airstream velocity. Airstream guidance, deflection and baffling are made adjustable to tune the system to accommodate for variations in the consistency of waste.

Abstract: For separating nuts from orchard trash in a windrow, the mixture of nuts and trash is picked up and deposited on the forward end of a foraminous conveyor enclosed by a housing connected to a fan inducing a vigorous flow of air through the conveyor. Variously arranged baffles, walls and guide plates direct the air rearwardly to enhance separation capacity and form settling zones to increase separation efficiency. Provision is also made for abruptly changing the direction of movement of the nut and trash supporting upper run of the conveyor to dislodge and tumble the nuts and the trash as they traverse the separation zone where the flow of air emerges through the upper run, thereby effecting even more rapid and efficient separation.

Abstract: A powder dispensing assembly including an elongated chute having opposite ends pivotally supported for rotation about a pivot axis within an elongated housing and having a funnel-shaped cross section with a wide upper portion and a narrow lower portion. A dispensing platform is integral with the rear wall of the chute and extends forwardly beneath the front wall and slopes upwardly to a lip over which particles of powder move to define a falling curtain of powder particles. A supply platform is supported just above the pivot axis and receives powder from an elongated slot and supplies powder to the dispensing platform as the powder falls downwardly through the chute. The supply platform is wider than the angle of repose of the powder supplied thereto so that when the supply platform is not moving powder is not being supplied to the lower dispensing platform. An electromagnet cooperates with a spring plate which is, in turn, connected by a rod through the housing to the rear wall of the chute.

Abstract: A harvester for beans and like crop includes a pick-up reel having a width equal to the overall width of the harvester and leading to a first, cleaning, conveyor which terminates at an air passage incorporating a fan for generating a generally vertical air flow. Where the vertical air passage meets the cleaning conveyor, a rotary valve is provided which permits the passage of the beans and other parts of the crop but prevents or at least restricts the passage of the air flow into the space above the upper run of the conveyor.The rotary valve may take the form of a rotary vaned assembly having six vanes each of which is secured to one face of a hexagonal shaft and various forms of rotary valve are also described.